I see 2 key questions to resolve.
(1) Tua Tagovailoa's health status. How far away is he from 100% healthy and able to start? Miami has the luxury of being able to sit him on the bench for the next year to learn from Fitz how to lead - how to read defenses - how to inspire teammates - how to handle the media, etc. And we still have Rosen as a backup if the bearded one gets injured. Not all of our competitors have that sort of luxury to be able to just let Tua sit and learn.
(2) How big is the perceived talent variance between Tua, Herbert and Love? GM Chris Grier, Reggie McKenzie (who's been quietly evaluating all emerging college talent for the past year while Grier accumulated Draftpicks) and others in the Dolphins organization have definitely put the work in to determine their respective college player rankings. While most on here probably believe that Tua is at least the second best QB in the Draft (let's assume that Joe Burrow will go to the Bengals - given owner and GM, Mike Brown's track record of never, ever trading away a high Draft pick). There is still the possibility that the differential between Herbert or Love and Tua is small. Tua is extremely accurate. However, don't forget the incredible talent at Alabama that he has been throwing to. Jerry Jeudy is very, very good. Henry Ruggs, DeVonta Smith and others are all good, plus the stable of great RBs to run the ball. However, while Herbert has a really big arm, he had comparatively limited talent around him at the Ducks. Yes, he's an obvious introvert, but he does have talent. What could he do with WR's like DeVante Parker to throw to?
Remember, Mike Evans helped to make Johnny Manziel look good at Texas A & M, and get drafted in the first round.